Steamy days, sultry nights and swarming bugs all make up the thrum of life in the heart of summer. But more and more, our summers are assaulted by the bloodsucking kind of bugs, namely mosquitoes and ticks.

More than a nuisance, new species can impact our health and indicate larger environmental trends.

Beautiful And Adaptable

One relative newcomer prowling the scene is the Asian tiger mosquito. Named for its unique markings, it is black with white stripes.

"It's actually — if I could go out on a limb here — a very beautiful mosquito," says entomologist Brian Allan, assistant professor at the University of Illinois at Urbana-Champaign.

Stripes aside, the Asian tiger mosquito could also have been named for its aggressiveness, biting fast enough to escape swatting.

"It's also very adaptable in terms of the types of habitats it occupies; it can live inside of houses as well as outside," Allan says. And it thrives in tropical climates as well as temperate ones.

The Asian tiger mosquito probably came to this country in the 1980s, carried in the standing water found in used tires shipped from Asia.

Since its arrival, it's only been spreading, outcompeting native mosquitoes in urban and suburban areas in the South, the Midwest, on the East Coast and Hawaii.

Though still rare in this country, the Asian tiger mosquito has caused outbreaks of the dengue virus.

"Many diseases are starting to occur in places where they simply didn't occur previously," Allan says, including the West Nile virus.

Expanding Territory

Far more common than West Nile virus in the U.S. is Lyme disease.

"The distributions of ticks and the distributions of the pathogens they transmit to humans are increasing in many parts of North America," Allan says.

Notably, the blacklegged tick, better known as the deer tick, has been spreading.

"In recent history, it had two areas in which it generally occurred: the Northeastern United States and the upper-Midwest," Allan says.

Part of the problem are humans. As we take up more room, deer and mice — tasty tick hosts — are being pushed into our space, where they face fewer natural predators.

Another factor is climate change.

"Warmer winters could result in greater over-winter survival of both ticks and mosquitoes, and by that exacerbate the prevalence of disease in humans," Allan says.

Larger Than The Insects

But this expanding distribution of mosquitoes and ticks is emblematic of a bigger issue, he says.

"We are having a problem with invasive species of all varieties," he says, including plants, animals and bugs. "This is something of an overlooked crisis, in terms of its biological impact."

Global commerce, expanding development, even the pet trade, all are factors.

"They all in some sense or another tie to human globalization," Allan says, "and the point that human movements and human connectiveness are greater now than any point in human history."

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Transcript

JACKI LYDEN, HOST:

OK, you don't have to see to recognize this sound.

(SOUNDBITE OF SWARMING BUGS)

LYDEN: Swarming bugs. It's part of what makes the thrum of life in the heart of summer. More and more, though, we're coming into contact with the nasty, bloodsucking kind of bugs, namely mosquitoes and ticks. One relative newcomer prowling the scene is the Asian tiger mosquito.

BRIAN ALLAN: It's black with white stripes. It's actually - if I could go out on a limb here - a very beautiful mosquito.

LYDEN: Spoken like a true entomologist. That's Brian Allan, assistant professor at the University of Illinois Urbana-Champaign. But swashbuckling stripes aside, the Asian tiger mosquito could also have been named for its aggressiveness, biting fast enough to escape swatting.

ALLAN: It's also very adaptable in terms of the types of habitats it occupies. It can live inside houses as well as outside of houses.

LYDEN: And it thrives in tropical climates as well as temperate ones. So how did the Asian tiger mosquitoes get here? They probably hatched in the standing water inside used tires shipped over from Asia in the 1980s. And since then, they've only been spreading, outcompeting native mosquitoes in urban and suburban areas in the South, the Midwest, on the East Coast and Hawaii causing outbreaks of the dengue virus.

ALLAN: Many diseases are starting to occur in places where they simply didn't occur previously.

LYDEN: Such as the West Nile virus. But far more common in this country is Lyme disease.

ALLAN: The distributions of ticks and the distributions of the pathogens they transmit to humans are increasing in many parts of North America.

LYDEN: Notably, the blacklegged tick, better known as the deer tick.

ALLAN: In recent history, it had two areas in which it generally occurred: the Northeastern United States and the Upper Midwest.

LYDEN: And over the years, those two areas have grown so big they're practically touching. Part of the problem is us. As we take up more room, deer and mice - tasty tick hosts - are being pushed into our space, where they face fewer natural predators.

ALLAN: And so these really large animal populations may be more conducive then to the establishment of these ticks in new areas.

LYDEN: Another factor, climate change.

ALLAN: Warmer winters could result in greater over-winter survival of both ticks and mosquitoes, and by that exacerbate the prevalence of disease in humans.

LYDEN: But this expanding bug population is emblematic of a bigger problems, says Allan.

ALLAN: We're having a problem with invasive species of all varieties. And so this is something of a overlooked crisis, in terms of its biological impact.

LYDEN: Global commerce, expanding development, even the pet trade, are all factors.

ALLAN: They all, in some sense or another, tie to human globalization and the point that human movements and human connectedness are greater now than at any point in human history. And there are some real biological consequences for that.